In the existing liquid crystal display technology, liquid crystal is generally injected between glass substrates to form a liquid crystal display panel. With the increase or decrease of environment temperature, the glass substrates and the liquid crystal may expand or shrink. The liquid crystal has a thermal expansion coefficient which is much larger than other components in a liquid crystal cell like glass substrates, and this will introduce problems. In one aspect, at high temperature, the liquid crystal in the liquid crystal display panel thermally expands to an extent significantly larger than other components, a thickness of the liquid crystal cell is increased, and the spacers cannot thermally expand to the same extent. In this case, liquid crystal in the liquid crystal display panel which is oriented vertically tends to move downward due to gravity. This is so-called gravity mura at high temperature. In another aspect, when the liquid crystal display panel is at low temperature, the liquid crystal thermally shrinks to an extent greater than other components. Namely, in case the thickness of the liquid crystal cell is kept constant, the liquid crystal will not fully fill the liquid crystal cell and thus vacuum bubbles will appear. This is so-called bubbles at low temperature. These defects restrict the application conditions of the liquid crystal display device, affect the display effect of the liquid crystal display device, and thus impair user experience. During the fabricating process, the allowable controlling range for amount of liquid crystal in case of defects of gravity mura at high temperature and bubbles at low temperature is referred to as LC Margin.
There is a need in the art for improving the liquid crystal display panel in terms of defects of gravity mura at high temperature and bubbles at low temperature.